// The application: the design script, the two run modes (the linear modal
// model on the CPU workers and the full nonlinear simulation on the GPU),
// the plate view, the movie, the audio, and the spectrogram.

import { compileDesign, evaluatePlate, isFlat, profileStats, type Design, DesignError } from "./design.ts";
import { PRESETS, DEFAULT_PRESET, presetById } from "./presets.ts";
import {
  type Plate,
  type SimParams,
  defaultParams,
  countInside,
  massProperties,
  meanThickness,
  thicknessRange,
  standRates,
  strikePoint,
  strikePatch,
  listenerPosition,
  dispersionFrequency,
  inPlaneSpeed,
  CFL,
} from "./params.ts";
import { fitSigma, fittedRate, t60At, LN1000, decayRate } from "./loss.ts";
import { assemble, type LinearSystem } from "./model/assemble.ts";
import { maxAngularFrequency, fullLoss, type FullLoss } from "./model/reference.ts";
import { type ModeSet } from "./modal/modes.ts";
import { WorkerPool } from "./modal/pool.ts";
import { modalModel, modeShapeOnGrid, type ModalModel, type ContactResult } from "./modal/synth.ts";
import { Simulation } from "./sim/simulation.ts";
import { runSelfTest } from "./sim/selftest.ts";
import { PlateRenderer, type ViewMode, type ColorMode } from "./render/renderer.ts";
import { Spectrogram } from "./audio/spectrogram.ts";
import { Player } from "./audio/player.ts";
import { encodeWav } from "./audio/wav.ts";
import { levelGain, applyLevel, peakDbfs, peakSpl, loudness, type LevelMode } from "./audio/level.ts";
import { DesignEditor } from "./ui/editor.ts";
import { ParamForm, formatNumber } from "./ui/form.ts";
import { ModeBrowser } from "./ui/modes.ts";
import { Tutorial } from "./tutorial/tutorial.ts";
import { type Memo, type TutorialContext, type TutorialHost } from "./tutorial/steps.ts";

type RunMode = "linear" | "full";
type ViewState = "design" | "mode" | "live" | "movie";

const $ = <T extends HTMLElement>(id: string): T => document.getElementById(id) as T;


/** A recording: the listener signal and the movie of one run, from either model. */
interface Recording {
  audio: Float32Array;
  samples: number;
  fs: number;
  frames: Float32Array[];
  fps: number;
  source: RunMode;
}

class App {
  // GPU
  device: GPUDevice | null = null;
  // Design and plate
  design: Design | null = null;
  plate: Plate | null = null;
  plateSpacing = 0;
  designGeneration = 0;
  // Linear model
  pool: WorkerPool | null = null;
  sys: LinearSystem | null = null;
  modes: ModeSet | null = null;
  model: ModalModel | null = null;
  modesBusy: Promise<void> = Promise.resolve();
  /** Modes of recent designs, keyed by the script, the spacing and the cutoff; the newest entry is last. */
  modesCache = new Map<string, { sys: LinearSystem; modes: ModeSet; model: ModalModel }>();
  headProgress!: HTMLDivElement;
  /** The cache key of the modes the pool currently holds. */
  currentModesKey: string | null = null;
  headProgressBar!: HTMLDivElement;
  synthBusy = false;
  synthPending = false;
  synthesized = false;
  lastContact: ContactResult | null = null;
  // Full simulation
  sim: Simulation | null = null;
  running = false;
  paused = false;
  // Recording and view
  rec: Recording | null = null;
  view: ViewState = "design";
  frameIndex = 0;
  runMode: RunMode = "linear";
  // UI
  editor!: DesignEditor;
  form!: ParamForm;
  modeBrowser!: ModeBrowser;
  renderer!: PlateRenderer;
  spec!: Spectrogram;
  tutorial: Tutorial | null = null;
  tutorialMemo: Memo = {};
  specOpts = { window: 2048, logFreq: false };
  specWinSel!: HTMLSelectElement;
  specLogChk!: HTMLInputElement;
  colorSel!: HTMLSelectElement;
  player = new Player();
  levelMode: LevelMode = "absolute";
  gainDb = -40;
  showTicks = true;
  viewOpts = { mode: "3d" as ViewMode, color: "height" as ColorMode, showProfile: true, exaggeration: 1, range: 0 };
  // Controls
  runModeSel!: HTMLSelectElement;
  durationInput!: HTMLInputElement;
  startBtn!: HTMLButtonElement;
  pauseBtn!: HTMLButtonElement;
  stopBtn!: HTMLButtonElement;
  continueBtn!: HTMLButtonElement;
  runStatus!: HTMLDivElement;
  scrub!: HTMLInputElement;
  timeLabel!: HTMLSpanElement;
  playBtn!: HTMLButtonElement;
  liveBtn!: HTMLButtonElement;
  designBtn!: HTMLButtonElement;
  peakLabel!: HTMLSpanElement;
  downloadBtn!: HTMLButtonElement;
  overlay!: HTMLDivElement;
  synthTimer: number | null = null;
  // Loudness warning
  loudWarn!: HTMLDivElement;
  loudWarnText!: HTMLSpanElement;
  loudPlayBtn!: HTMLButtonElement;
  loudGo: (() => void) | null = null;
  /** Whether the user has agreed to play the current signal; any change of the recording, the level mode or the gain resets it. */
  loudAccepted = false;

  async init(): Promise<void> {
    const url = new URLSearchParams(location.search);
    if (!url.has("nogpu") && navigator.gpu) {
      try {
        const adapter = await navigator.gpu.requestAdapter();
        if (adapter) this.device = await adapter.requestDevice();
      } catch (e) {
        console.warn("WebGPU unavailable", e);
      }
    }
    if (typeof Worker !== "undefined") this.pool = new WorkerPool(WorkerPool.defaultSize());

    this.buildControls();
    this.buildForm();
    this.buildViewToolbar();
    this.buildMovieToolbar();
    this.buildSpecToolbar();
    this.buildSplitter();

    this.renderer = new PlateRenderer($("view"), this.device);
    if (!this.renderer.has3d) this.viewOpts.mode = "2d";
    this.renderer.setOptions(this.viewOpts);
    this.overlay = $("viewOverlay");
    const p = this.form.get();
    this.spec = new Spectrogram($("spec"), { fs: p.fs, window: 2048, hop: 256, maxHz: 12000, dbRange: 80, logFreq: false });
    this.spec.setDuration(p.duration);
    this.modeBrowser = new ModeBrowser($("modes"), (m) => this.showMode(m));
    this.editor = new DesignEditor($("design"), { onSource: (src) => this.onSource(src) });
    this.tutorial = new Tutorial($("tutorial"), this.tutorialHost(), (open) => {
      $("tutorialBtn").classList.toggle("active", open);
      this.renderer.resize(); this.spec.resize();
    });
    $("tutorialBtn").addEventListener("click", () => this.tutorial?.toggle());

    if (url.has("mode")) this.setRunMode(url.get("mode") === "full" ? "full" : "linear");
    else this.setRunMode(this.device ? "linear" : "linear");
    // The parameters come first, so that the preset is evaluated at the requested spacing.
    this.form.applyUrl(url);
    this.durationInput.value = String(this.form.get().duration);
    const preset = url.get("preset");
    this.editor.selectPreset(preset && presetById(preset) ? preset : DEFAULT_PRESET);
    // The tutorial opens on request (?tutorial=1 or ?tutorial=<step id>) or when it was open last time.
    const tut = url.get("tutorial");
    if (tut !== null) this.tutorial.open(tut === "1" || tut === "" ? undefined : tut);
    else if (this.tutorial.wasOpen()) this.tutorial.open();

    const loop = () => {
      this.renderer.render();
      requestAnimationFrame(loop);
    };
    requestAnimationFrame(loop);
    window.addEventListener("resize", () => { this.renderer.resize(); this.spec.resize(); });
    this.renderer.resize();
    this.spec.resize();

    // Test hooks.
    (window as unknown as { cymbalsim: unknown }).cymbalsim = {
      app: this,
      selftest: () => this.selfTest(),
      runLinear: () => this.runLinear(),
      runFull: () => this.runFull(),
      modesReady: () => this.modesBusy,
      status: () => this.testStatus(),
      tutorial: this.tutorial,
    };
    if (url.has("selftest")) {
      const r = await this.selfTest();
      this.overlay.textContent = r;
    }
    if (url.has("autostart")) {
      await this.modesBusy;
      this.start();
    }
  }

  // ---------- Controls ----------

  private buildControls(): void {
    const c = $("controls");
    this.runModeSel = document.createElement("select");
    this.runModeSel.innerHTML = `<option value="linear">Linear (modal)</option><option value="full">Full (nonlinear, GPU)</option>`;
    this.runModeSel.addEventListener("change", () => this.setRunMode(this.runModeSel.value as RunMode));
    const durLabel = document.createElement("label");
    durLabel.textContent = "Duration";
    this.durationInput = document.createElement("input");
    this.durationInput.type = "number"; this.durationInput.min = "0.1"; this.durationInput.step = "0.5"; this.durationInput.style.width = "60px";
    this.durationInput.addEventListener("change", () => {
      const d = Math.max(0.1, Number(this.durationInput.value) || 1);
      this.form.set("duration", d);
      this.spec.setDuration(d);
      if (this.sim) this.sim.setDuration(d);
      this.updateButtons();
    });
    const s = document.createElement("span"); s.textContent = " s";
    durLabel.append(this.durationInput, s);
    this.startBtn = this.button("Start", () => this.start(), "primary");
    this.pauseBtn = this.button("Pause", () => this.pause());
    this.stopBtn = this.button("Stop", () => this.stopRun());
    this.continueBtn = this.button("Continue", () => this.continueRun());
    c.append(this.runModeSel, durLabel, this.startBtn, this.pauseBtn, this.stopBtn, this.continueBtn);
    this.headProgress = document.createElement("div");
    this.headProgress.className = "progress";
    this.headProgress.hidden = true;
    this.headProgressBar = document.createElement("div");
    this.headProgress.append(this.headProgressBar);
    this.runStatus = document.createElement("div");
    this.runStatus.className = "status";
    $("sidebarHead").append(this.headProgress, this.runStatus);
  }

  /** The progress bar under the run controls (fraction 0..1, or null to hide) with a status message. */
  private setProgress(fraction: number | null, message?: string): void {
    this.headProgress.hidden = fraction === null;
    if (fraction !== null) this.headProgressBar.style.width = `${Math.round(100 * fraction)}%`;
    if (message !== undefined) this.runStatus.textContent = message;
  }

  private button(label: string, onClick: () => void, cls = ""): HTMLButtonElement {
    const b = document.createElement("button");
    b.textContent = label;
    if (cls) b.className = cls;
    b.addEventListener("click", onClick);
    return b;
  }

  private buildForm(): void {
    this.form = new ParamForm(
      $("params"),
      [
        {
          title: "Strike",
          notes: true,
          fields: [
            { key: "strikeFracX", label: "Position x (fraction of width)", step: 0.05, min: 0, max: 1 },
            { key: "strikeFracY", label: "Position y (fraction of height)", step: 0.05, min: 0, max: 1 },
            { key: "strikeVelocity", label: "Stick speed", unit: "m/s", step: 0.5, min: 0.01 },
            { key: "stickMass", label: "Stick mass", unit: "g", scale: 1e-3, step: 5, min: 1 },
            { key: "contactStiffness", label: "Contact stiffness K", unit: "N/m^a", step: 1e8, min: 1e5 },
            { key: "contactExponent", label: "Contact exponent a", step: 0.1, min: 1, max: 3 },
            { key: "contactRadius", label: "Tip radius", unit: "mm", scale: 1e-3, step: 1, min: 0.5 },
          ],
        },
        {
          title: "Listener",
          fields: [
            { key: "listenerDist", label: "Distance", unit: "m", step: 0.1, min: 0.05, live: true },
            { key: "listenerAngle", label: "Angle from the normal", unit: "deg", step: 5, min: 0, max: 90, live: true },
            { key: "listenerAzimuth", label: "Azimuth", unit: "deg", step: 15, min: -180, max: 180, live: true },
          ],
        },
        {
          title: "Grid and numerics",
          notes: true,
          fields: [
            { key: "spacing", label: "Grid spacing", unit: "mm", scale: 1e-3, step: 1, min: 2 },
            { key: "modeMaxFreq", label: "Modes up to", unit: "Hz", step: 1000, min: 200 },
            { key: "padLiftoff", label: "Pads lift off (full model)", kind: "checkbox" },
            { key: "fs", label: "Sample rate", kind: "select", options: [{ value: 44100, label: "44.1 kHz" }, { value: 48000, label: "48 kHz" }, { value: 96000, label: "96 kHz" }] },
            { key: "fps", label: "Movie frame rate", kind: "select", options: [{ value: 60, label: "60" }, { value: 120, label: "120" }, { value: 240, label: "240" }] },
          ],
        },
      ],
      defaultParams,
      (key, _value, live) => this.onParam(key, live),
    );
  }

  private onParam(key: keyof SimParams, live: boolean): void {
    const p = this.form.get();
    if (key === "spacing" || key === "modeMaxFreq" || key === "fs") {
      if (this.design) this.rebuildPlate(this.design);
      return;
    }
    if (key === "fps") { this.updateNotes(); return; }
    if (key === "padLiftoff") { this.updateNotes(); return; }
    if (live && this.sim) this.sim.setListener(p);
    if (key.startsWith("strike") || key.startsWith("stick") || key.startsWith("contact") || key.startsWith("listener")) {
      this.updateMarkers();
      this.updateNotes();
      if (this.runMode === "linear" && this.synthesized) this.scheduleSynth();
    }
    this.tutorial?.refresh();
  }

  private buildViewToolbar(): void {
    const t = $("viewToolbar");
    const modeSel = document.createElement("select");
    modeSel.innerHTML = `<option value="3d">3D</option><option value="2d">2D</option>`;
    modeSel.addEventListener("change", () => { this.viewOpts.mode = modeSel.value as ViewMode; this.renderer.setOptions(this.viewOpts); });
    const colorSel = document.createElement("select");
    colorSel.innerHTML = `<option value="height">Height</option><option value="thickness">Thickness</option>`;
    colorSel.addEventListener("change", () => { this.viewOpts.color = colorSel.value as ColorMode; this.renderer.setOptions(this.viewOpts); });
    this.colorSel = colorSel;
    const exag = document.createElement("input");
    exag.type = "number"; exag.min = "1"; exag.step = "5"; exag.value = String(this.viewOpts.exaggeration); exag.style.width = "60px";
    exag.addEventListener("change", () => { this.viewOpts.exaggeration = Math.max(0.1, Number(exag.value) || 1); this.renderer.setOptions(this.viewOpts); });
    const range = document.createElement("input");
    range.type = "number"; range.min = "0"; range.step = "0.1"; range.value = "0"; range.style.width = "60px";
    range.addEventListener("change", () => { this.viewOpts.range = Math.max(0, Number(range.value) || 0) * 1e-3; this.renderer.setOptions(this.viewOpts); });
    const prof = document.createElement("input");
    prof.type = "checkbox"; prof.checked = this.viewOpts.showProfile;
    prof.addEventListener("change", () => { this.viewOpts.showProfile = prof.checked; this.renderer.setOptions(this.viewOpts); });
    const lab = (text: string, ...els: HTMLElement[]) => { const l = document.createElement("label"); l.append(text, ...els); return l; };
    t.append(lab("View", modeSel), lab("Color", colorSel), lab("Exaggeration", exag), lab("Range (mm, 0 = auto)", range), lab("Show profile", prof));
    if (!this.device) {
      modeSel.value = "2d"; modeSel.disabled = true;
      const w = document.createElement("span"); w.id = "nogpu"; w.textContent = "WebGPU is not available: the 2D view and the linear model only.";
      t.append(w);
    }
  }

  private buildMovieToolbar(): void {
    const t = $("movieToolbar");
    this.playBtn = this.button("Play", () => this.togglePlay());
    this.liveBtn = this.button("Live", () => this.setView("live"));
    this.designBtn = this.button("Design", () => this.setView("design"));
    this.scrub = document.createElement("input");
    this.scrub.type = "range"; this.scrub.className = "scrub"; this.scrub.min = "0"; this.scrub.max = "0"; this.scrub.value = "0";
    this.scrub.addEventListener("input", () => { this.frameIndex = Number(this.scrub.value); this.setView("movie"); this.showFrame(); });
    this.timeLabel = document.createElement("span");
    this.timeLabel.textContent = "0.000 s";
    const levelSel = document.createElement("select");
    levelSel.innerHTML = `<option value="absolute">Absolute level</option><option value="loudness">Normalize loudness</option><option value="peak">Normalize peak</option>`;
    levelSel.addEventListener("change", () => { this.levelMode = levelSel.value as LevelMode; this.updatePeak(); });
    const gain = document.createElement("input");
    gain.type = "range"; gain.min = "-60"; gain.max = "40"; gain.step = "1"; gain.value = String(this.gainDb);
    const gainLabel = document.createElement("span"); gainLabel.textContent = `${this.gainDb} dB`;
    gain.addEventListener("input", () => { this.gainDb = Number(gain.value); gainLabel.textContent = `${this.gainDb} dB`; this.updatePeak(); });
    this.peakLabel = document.createElement("span");
    this.downloadBtn = this.button("Download .wav", () => this.download());
    const lab = (text: string, ...els: HTMLElement[]) => { const l = document.createElement("label"); l.append(text, ...els); return l; };
    t.append(this.playBtn, this.liveBtn, this.designBtn, this.scrub, this.timeLabel, levelSel, lab("Gain", gain, gainLabel), this.peakLabel, this.downloadBtn);
    // The loudness warning, shown in place of playing when the signal peaks near full scale.
    this.loudWarn = document.createElement("div");
    this.loudWarn.className = "loud-warn";
    this.loudWarn.hidden = true;
    this.loudWarnText = document.createElement("span");
    this.loudPlayBtn = this.button("Play anyway", () => { const go = this.loudGo; this.hideLoudWarning(); go?.(); });
    const cancel = this.button("Cancel", () => this.hideLoudWarning());
    this.loudWarn.append(this.loudWarnText, this.loudPlayBtn, cancel);
    t.append(this.loudWarn);
  }

  /** Shows the loudness warning; `go` starts the playback if the user accepts. */
  private showLoudWarning(peakDb: number, shortTermDb: number, go: () => void): void {
    this.loudGo = go;
    this.loudWarnText.textContent = `This recording is loud (peak ${peakDb.toFixed(1)} dBFS, short-term level ${shortTermDb.toFixed(1)} dBFS), enough to hurt in headphones. Turn your volume down before playing.`;
    this.loudWarn.hidden = false;
    this.loudPlayBtn.focus();
  }

  private hideLoudWarning(): void {
    this.loudWarn.hidden = true;
    this.loudGo = null;
  }

  private buildSpecToolbar(): void {
    const t = $("specToolbar");
    const sel = (opts: [string, string][], value: string, onChange: (v: string) => void) => {
      const s = document.createElement("select");
      for (const [v, l] of opts) { const o = document.createElement("option"); o.value = v; o.textContent = l; s.append(o); }
      s.value = value;
      s.addEventListener("change", () => onChange(s.value));
      return s;
    };
    const lab = (text: string, ...els: HTMLElement[]) => { const l = document.createElement("label"); l.append(text, ...els); return l; };
    const win = sel([["512", "512"], ["1024", "1024"], ["2048", "2048"], ["4096", "4096"]], "2048", (v) => { this.specOpts.window = Number(v); this.spec.setOptions({ window: Number(v), hop: Number(v) / 8 }); this.tutorial?.refresh(); });
    const maxHz = sel([["4000", "4 kHz"], ["8000", "8 kHz"], ["12000", "12 kHz"], ["16000", "16 kHz"], ["20000", "20 kHz"]], "12000", (v) => this.spec.setOptions({ maxHz: Number(v) }));
    const db = sel([["60", "60 dB"], ["80", "80 dB"], ["100", "100 dB"]], "80", (v) => this.spec.setOptions({ dbRange: Number(v) }));
    const log = document.createElement("input"); log.type = "checkbox";
    log.addEventListener("change", () => { this.specOpts.logFreq = log.checked; this.spec.setOptions({ logFreq: log.checked }); this.tutorial?.refresh(); });
    this.specWinSel = win; this.specLogChk = log;
    const ticks = document.createElement("input"); ticks.type = "checkbox"; ticks.checked = this.showTicks;
    ticks.addEventListener("change", () => { this.showTicks = ticks.checked; this.updateTicks(); });
    t.append(lab("Spectrogram window", win), lab("Max", maxHz), lab("Range", db), lab("Log frequency", log), lab("Modal frequencies", ticks));
  }

  private buildSplitter(): void {
    const sp = $("splitter"), sb = $("sidebar");
    const saved = localStorage.getItem("cymbalsim.sidebar");
    if (saved) sb.style.width = saved;
    let dragging = false;
    sp.addEventListener("mousedown", (e) => { dragging = true; e.preventDefault(); });
    window.addEventListener("mousemove", (e) => {
      if (!dragging) return;
      const w = Math.max(280, Math.min(window.innerWidth - 300, e.clientX));
      sb.style.width = `${w}px`;
      this.renderer.resize(); this.spec.resize();
    });
    window.addEventListener("mouseup", () => { if (dragging) { dragging = false; localStorage.setItem("cymbalsim.sidebar", sb.style.width); } });
    sp.addEventListener("dblclick", () => { sb.style.width = ""; localStorage.removeItem("cymbalsim.sidebar"); this.renderer.resize(); this.spec.resize(); });
  }

  // ---------- Design ----------

  private onSource(source: string): void {
    if (this.running) return;
    let d: Design;
    try {
      d = compileDesign(source);
    } catch (e) {
      this.editor.setStatus(e instanceof Error ? e.message : String(e), "error");
      return;
    }
    this.editor.setStatus(`Compiled: ${d.name}`, "ok");
    this.rebuildPlate(d);
  }

  private rebuildPlate(d: Design): void {
    const p = this.form.get();
    let plate: Plate;
    try {
      plate = evaluatePlate(d, p.spacing);
    } catch (e) {
      this.editor.setStatus(e instanceof DesignError ? e.message : String(e), "error");
      return;
    }
    this.design = d;
    this.plate = plate;
    this.plateSpacing = p.spacing;
    this.designGeneration++;
    this.modes = null; this.model = null; this.sys = null;
    this.synthesized = false;
    this.lastContact = null;
    this.rec = null;
    this.spec.reset();
    this.spec.setOptions({ fs: p.fs });
    this.renderer.setPlate(plate);
    this.setView("design");
    this.updateMarkers();
    this.updateDesignInfo();
    this.updateNotes();
    this.updateButtons();
    if (this.runMode === "linear") this.useCachedModes();
    else this.modeBrowser.clear("Switch to the linear model to compute the modes.");
    this.tutorial?.refresh();
  }

  /** The cache key of the modes of the current design and numerics. */
  private modesKey(): string | null {
    if (!this.design || !this.plate) return null;
    const p = this.form.get();
    return `${this.plateSpacing}|${Math.min(p.modeMaxFreq, p.fs / 2)}|${this.design.source}`;
  }

  /** Installs cached modes for the current design if there are any; otherwise leaves the browser empty. */
  private useCachedModes(): void {
    const key = this.modesKey();
    const hit = key ? this.modesCache.get(key) : undefined;
    if (hit && this.plate) {
      this.installModes(hit.sys, hit.modes, hit.model, null);
      if (this.pool) void this.pool.setModel(hit.model);
    } else this.modeBrowser.clear("Press Synthesize to compute the modes of this design.");
  }

  /** Shows a mode set in the browser, the notes and the spectrogram ticks. */
  private installModes(sys: LinearSystem, modes: ModeSet, model: ModalModel, secs: number | null): void {
    const pl = this.plate!;
    const p = this.form.get();
    const fMax = Math.min(p.modeMaxFreq, p.fs / 2);
    this.sys = sys; this.modes = modes; this.model = model;
    const rows = Array.from(modes.freqs).map((f, m) => ({ freq: f, t60: LN1000 / Math.min(decayRate(pl.loss, f) + model.padSigma[m], 0.99 * 2 * Math.PI * f) }));
    const kind = sys.fields === 1 ? "bending modes" : "modes (bending coupled to stretching)";
    const when = secs === null ? "cached" : `in ${secs.toFixed(1)} s`;
    this.modeBrowser.setModes(rows, `${modes.count} ${kind} up to ${(fMax / 1e3).toFixed(1)} kHz, ${when} (${sys.n} unknowns${modes.missing ? `, ${modes.missing} missing` : ""}). Click a mode to see its shape.`);
    this.updateNotes();
    this.updateTicks();
    this.updateButtons();
    this.tutorial?.refresh();
  }

  private updateDesignInfo(): void {
    const pl = this.plate;
    if (!pl) return;
    const p = this.form.get();
    const g = pl.grid;
    const { mass } = massProperties(pl);
    const hr = thicknessRange(pl);
    const ps = profileStats(pl);
    const sr = standRates(pl);
    const lines: string[] = [];
    lines.push(`${pl.name}: ${(pl.Lx * 1e3).toFixed(0)} x ${(pl.Ly * 1e3).toFixed(0)} mm, E = ${(pl.mat.E / 1e9).toFixed(0)} GPa, nu = ${pl.mat.nu}, rho = ${pl.mat.rho} kg/m^3`);
    lines.push(`Thickness ${(hr.min * 1e3).toFixed(2)} to ${(hr.max * 1e3).toFixed(2)} mm, mass ${(mass * 1e3).toFixed(0)} g, grid ${g.nx} x ${g.ny} at ${(g.hx * 1e3).toFixed(2)} mm (${countInside(g)} nodes)`);
    if (ps.peakToPeak > 0) {
      const warn = ps.maxSlope > 0.1 ? ` <span class="warn">(above the shallow-shell range of about 0.1)</span>` : "";
      lines.push(`Profile ${(ps.peakToPeak * 1e3).toFixed(1)} mm peak to peak, largest slope ${ps.maxSlope.toFixed(3)}${warn}`);
    } else lines.push("Flat plate (no profile): the linear model is bending only");
    if (pl.stand && sr) {
      const pad = pl.stand.pad;
      lines.push(`Stand: ${pl.stand.topPad ? "two pads" : "bottom pad only"}, ${(pad.innerRadius * 1e3).toFixed(0)} to ${(pad.outerRadius * 1e3).toFixed(0)} mm, ${(pad.thickness * 1e3).toFixed(0)} mm felt at ${(pad.E / 1e6).toFixed(2)} MPa; ${(sr.totalKw / 1e3).toFixed(0)} kN/m, bounce ${sr.bounceHz.toFixed(0)} Hz, ${sr.nodes.length} pad nodes, preload ${(sr.preloadTop * 1e3).toFixed(2)} / ${(sr.preloadBottom * 1e3).toFixed(2)} mm`);
    } else lines.push("Free plate (no stand)");
    lines.push(`Decay T60: ${t60At(pl.loss, 100).toFixed(2)} s at 100 Hz, ${t60At(pl.loss, 1000).toFixed(2)} s at 1 kHz, ${t60At(pl.loss, 5000).toFixed(2)} s at 5 kHz`);
    void p;
    $("designInfo").innerHTML = lines.join("\n");
  }

  private updateNotes(): void {
    const pl = this.plate;
    if (!pl) return;
    const p = this.form.get();
    const g = pl.grid;
    const hm = meanThickness(pl);
    const f3 = dispersionFrequency(pl.mat, hm, g.hx, 0.03), f10 = dispersionFrequency(pl.mat, hm, g.hx, 0.1);
    const wmax = maxAngularFrequency(g, pl.mat, thicknessRange(pl).max);
    const dtMax = (CFL * 2) / wmax;
    const sps = Math.ceil(1 / (p.fs * dtMax));
    const dt = 1 / (p.fs * sps);
    const fit = fitSigma(pl.loss, pl.mat, hm);
    const t60f = (f: number) => (LN1000 / fittedRate(fit, f)).toFixed(2);
    const lines = [
      `Grid ${g.nx} x ${g.ny}, ${countInside(g)} plate nodes. Grid dispersion lowers the bending partials by 3% near ${(f3 / 1e3).toFixed(1)} kHz and by 10% near ${(f10 / 1e3).toFixed(1)} kHz (at the mean thickness).`,
      `Linear model: modes up to ${(p.modeMaxFreq / 1e3).toFixed(1)} kHz${this.modes ? `, ${this.modes.count} found in ${this.modes.seconds.toFixed(1)} s` : ""}${this.modes && this.modes.missing ? ` <span class="warn">(${this.modes.missing} missing)</span>` : ""}.`,
      `Full model: time step ${(dt * 1e6).toFixed(2)} us (${sps} per sample, in-plane wave speed ${inPlaneSpeed(pl.mat).toFixed(0)} m/s), ${((p.duration * p.fs * sps) / 1e6).toFixed(1)} million steps for ${p.duration} s. Losses fitted as sigma0 = ${fit.sigma0.toFixed(2)} 1/s, sigma1 = ${fit.sigma1.toExponential(2)} m^2/s: T60 ${t60f(100)} / ${t60f(1000)} / ${t60f(5000)} s at 100 Hz / 1 kHz / 5 kHz (requested ${t60At(pl.loss, 100).toFixed(2)} / ${t60At(pl.loss, 1000).toFixed(2)} / ${t60At(pl.loss, 5000).toFixed(2)}).`,
    ];
    this.form.setNotes("Grid and numerics", lines.join("\n"));
    const patch = strikePatch(pl, p);
    const sp = strikePoint(pl, p);
    const sl = [`Strike at (${(sp.x * 1e3).toFixed(0)}, ${(sp.y * 1e3).toFixed(0)}) mm on ${patch.nodes.length} node${patch.nodes.length === 1 ? "" : "s"} (${(patch.mass * 1e3).toFixed(2)} g).`];
    if (this.lastContact) sl.push(`Last linear strike: peak force ${this.lastContact.peakForce.toFixed(0)} N, contact ${(this.lastContact.contactTime * 1e3).toFixed(2)} ms.`);
    if (this.sim) { const st = this.sim.status().stick; sl.push(`Full simulation: peak force ${st.maxForce.toFixed(0)} N${st.withdrawn ? ", stick withdrawn" : ""}.`); }
    this.form.setNotes("Strike", sl.join("\n"));
  }

  private updateMarkers(): void {
    const pl = this.plate;
    if (!pl) return;
    const p = this.form.get();
    const sp = strikePoint(pl, p);
    const L = listenerPosition(p);
    this.renderer.setMarkers({
      strike: { x: sp.x, y: sp.y, radius: p.contactRadius },
      stand: pl.stand ? { x: pl.stand.x, y: pl.stand.y, innerRadius: pl.stand.pad.innerRadius, outerRadius: pl.stand.pad.outerRadius } : null,
      listener: L,
    });
  }

  // ---------- Linear model ----------

  /** Computes the modes of the current design unless they are cached; resolves when they are installed (or with an error). */
  private computeModes(): Promise<void> {
    const pl = this.plate, gen = this.designGeneration, key = this.modesKey();
    if (!pl || !key) return Promise.resolve();
    const hit = this.modesCache.get(key);
    if (hit) {
      if (this.model !== hit.model) { this.installModes(hit.sys, hit.modes, hit.model, null); if (this.pool) return this.pool.setModel(hit.model); }
      return Promise.resolve();
    }
    const p = this.form.get();
    const fMax = Math.min(p.modeMaxFreq, p.fs / 2);
    this.modeBrowser.clear("Computing the modes...");
    this.setProgress(0, "Computing the modes...");
    this.updateButtons();
    this.modesBusy = this.modesBusy.then(async () => {
      if (gen !== this.designGeneration) return;
      const t0 = performance.now();
      let sys: LinearSystem;
      try {
        sys = assemble(pl);
      } catch (e) {
        this.setProgress(null, `Assembly failed: ${e instanceof Error ? e.message : String(e)}`);
        throw e;
      }
      let modes: ModeSet;
      try {
        if (this.pool) modes = await this.pool.modes(sys, fMax, (d, t) => { if (gen === this.designGeneration) this.setProgress(t ? d / t : 0, `Computing the modes: slice ${d} of ${t}`); });
        else {
          const { computeModes, localRunner } = await import("./modal/modes.ts");
          modes = await computeModes(sys, fMax, localRunner(sys));
        }
      } catch (e) {
        this.setProgress(null, `Mode computation failed: ${e instanceof Error ? e.message : String(e)}`);
        throw e;
      }
      const model = modalModel(pl, sys, modes);
      this.modesCache.set(key, { sys, modes, model });
      while (this.modesCache.size > 4) this.modesCache.delete(this.modesCache.keys().next().value!);
      if (gen !== this.designGeneration) { this.setProgress(null); return; }
      if (this.pool) await this.pool.setModel(model);
      this.setProgress(null, "");
      this.installModes(sys, modes, model, (performance.now() - t0) / 1000);
    });
    return this.modesBusy;
  }

  private showMode(m: number | null): void {
    if (m === null) { this.setView(this.rec ? "movie" : "design"); return; }
    if (!this.model) return;
    this.view = "mode";
    const shape = modeShapeOnGrid(this.model, m);
    // Scale the mass-normalized shape to a visible amplitude: 1 mm peak.
    let peak = 0;
    for (const v of shape) peak = Math.max(peak, Math.abs(v));
    const w = new Float32Array(shape.length);
    for (let k = 0; k < w.length; k++) w[k] = (shape[k] / (peak || 1)) * 1e-3;
    this.renderer.setField(w);
    this.overlay.textContent = `Mode ${m + 1}: ${this.model.freqs[m].toFixed(1)} Hz (shape scaled to 1 mm)`;
  }

  private scheduleSynth(): void {
    if (this.synthTimer !== null) clearTimeout(this.synthTimer);
    this.synthTimer = window.setTimeout(() => { this.synthTimer = null; void this.runLinear(); }, 250);
  }

  /** Makes sure the modes of the current design are computed and installed in the pool. */
  async ensureModes(): Promise<void> {
    if (!this.plate) return;
    if (!this.model || this.modesKey() !== this.currentModesKey) {
      await this.computeModes();
      this.currentModesKey = this.modesKey();
    }
  }

  /** Synthesizes the strike with the current parameters (linear model). */
  async runLinear(): Promise<void> {
    if (!this.plate) return;
    if (this.synthBusy) { this.synthPending = true; return; }
    try {
      await this.ensureModes();
    } catch {
      return;
    }
    const pl = this.plate, model = this.model;
    if (!pl || !model) return;
    this.synthBusy = true;
    const p = this.form.get();
    const gen = this.designGeneration;
    const t0 = performance.now();
    this.runStatus.textContent = "Synthesizing...";
    try {
      let audio: Float32Array, frames: Float32Array, nFrames: number, contact: ContactResult;
      if (this.pool) {
        const r = await this.pool.synthesize(model, pl, pl.loss, p, (a, c) => {
          if (gen !== this.designGeneration) return;
          this.installRecording(a, [], p, "linear");
          this.lastContact = c;
          this.runStatus.textContent = `Audio ready in ${((performance.now() - t0) / 1000).toFixed(2)} s; movie frames...`;
        });
        audio = r.audio; frames = r.frames; nFrames = r.nFrames; contact = r.contact;
      } else {
        const { synthesize } = await import("./modal/synth.ts");
        const r = synthesize(model, pl, pl.loss, p, true);
        audio = r.audio; frames = r.frames; nFrames = r.nFrames; contact = r.contact;
      }
      if (gen !== this.designGeneration) return;
      const n = pl.grid.n;
      const frameList: Float32Array[] = [];
      for (let f = 0; f < nFrames; f++) frameList.push(frames.subarray(f * n, (f + 1) * n));
      this.installRecording(audio, frameList, p, "linear");
      this.lastContact = contact;
      this.synthesized = true;
      const secs = (performance.now() - t0) / 1000;
      this.runStatus.textContent = `Linear model: ${model.count} modes, ${p.duration} s synthesized in ${secs.toFixed(2)} s. Peak ${peakSpl(audio).toFixed(0)} dB SPL, contact ${(contact.contactTime * 1e3).toFixed(2)} ms, peak force ${contact.peakForce.toFixed(0)} N.`;
      this.updateNotes();
    } catch (e) {
      this.runStatus.textContent = `Synthesis failed: ${e instanceof Error ? e.message : String(e)}`;
    } finally {
      this.synthBusy = false;
      this.tutorial?.refresh();
      if (this.synthPending) { this.synthPending = false; void this.runLinear(); }
    }
  }

  // ---------- Full simulation ----------

  async runFull(): Promise<void> {
    const pl = this.plate;
    if (!pl || !this.device || this.running) return;
    const p = this.form.get();
    this.sim?.destroy();
    const hm = meanThickness(pl);
    const fit = fitSigma(pl.loss, pl.mat, hm);
    const loss: FullLoss = fullLoss(fit, standRates(pl), decayRate(pl.loss, 5000));
    this.sim = new Simulation(this.device, pl, p, loss);
    this.rec = { audio: new Float32Array(0), samples: 0, fs: p.fs, frames: [new Float32Array(pl.grid.n)], fps: p.fps, source: "full" };
    this.spec.reset();
    this.spec.setOptions({ fs: p.fs });
    this.spec.setDuration(p.duration);
    this.running = true;
    this.paused = false;
    this.setLocked(true);
    this.setView("live");
    this.updateButtons();
    await this.fullLoop();
  }

  private async fullLoop(): Promise<void> {
    const sim = this.sim;
    if (!sim) return;
    const t0 = performance.now();
    let lastUi = 0;
    while (this.running && sim.phase === "recording") {
      if (this.paused) { await new Promise((r) => setTimeout(r, 50)); continue; }
      await sim.runBatch();
      if (!this.rec || this.sim !== sim) break;
      // New audio and frames.
      const rec = this.rec;
      const newSamples = sim.samples - rec.samples;
      if (newSamples > 0) {
        const chunk = sim.audio.subarray(rec.samples, sim.samples);
        this.spec.append(chunk);
        rec.audio = sim.audio; rec.samples = sim.samples;
      }
      rec.frames = sim.frames;
      if (this.view === "live") this.renderer.setField(sim.frames[sim.frames.length - 1]);
      const now = performance.now();
      if (now - lastUi > 100) {
        lastUi = now;
        const st = sim.status();
        const elapsed = (now - t0) / 1000;
        this.runStatus.textContent = `Full model: t = ${st.t.toFixed(3)} s, ${(st.totalSteps / elapsed / 1000).toFixed(0)}k steps/s (${(elapsed / Math.max(st.t, 1e-3)).toFixed(0)} s per second of sound), peak ${peakSpl(sim.recordedAudio()).toFixed(0)} dB SPL, stick force ${st.stick.force.toFixed(0)} N${st.delayClamped ? ", delay spread clamped" : ""}`;
        this.scrub.max = String(Math.max(0, rec.frames.length - 1));
        this.updatePeak();
      }
    }
    if (this.sim === sim) {
      this.running = false;
      this.setLocked(false);
      const st = sim.status();
      this.runStatus.textContent = `Full model: ${st.t.toFixed(2)} s recorded, peak ${peakSpl(sim.recordedAudio()).toFixed(0)} dB SPL, peak force ${st.stick.maxForce.toFixed(0)} N, largest displacement ${(st.wmax * 1e3).toFixed(2)} mm.`;
      if (this.rec) { this.rec.audio = sim.recordedAudio(); this.rec.samples = sim.samples; this.rec.frames = sim.frames; }
      this.updateNotes();
      this.updateButtons();
      this.updatePeak();
      this.tutorial?.refresh();
    }
  }

  // ---------- Run control ----------

  private setRunMode(mode: RunMode): void {
    if (mode === "full" && !this.device) mode = "linear";
    this.runMode = mode;
    this.runModeSel.value = mode;
    if (mode === "linear" && this.plate && !this.modes) this.useCachedModes();
    if (mode === "full") this.modeBrowser.clear("Switch to the linear model to compute the modes.");
    this.updateButtons();
    this.tutorial?.refresh();
  }

  private start(): void {
    if (this.runMode === "linear") void this.runLinear();
    else void this.runFull();
  }
  private pause(): void {
    if (!this.running) return;
    this.paused = !this.paused;
    this.pauseBtn.textContent = this.paused ? "Resume" : "Pause";
  }
  private stopRun(): void {
    if (this.sim && this.running) { this.sim.stop(); this.running = false; }
    this.paused = false;
    this.pauseBtn.textContent = "Pause";
    this.setLocked(false);
    this.updateButtons();
  }
  private continueRun(): void {
    const sim = this.sim;
    if (!sim || this.running || !sim.canContinue()) return;
    sim.setDuration(this.form.get().duration);
    this.running = true;
    this.setLocked(true);
    this.setView("live");
    this.updateButtons();
    void this.fullLoop();
  }

  private setLocked(locked: boolean): void {
    this.editor.setLocked(locked);
    this.form.setLocked(locked);
    this.runModeSel.disabled = locked;
  }

  private updateButtons(): void {
    const linear = this.runMode === "linear";
    const canLinear = linear && !!this.plate && !this.synthBusy;
    const canFull = !linear && !!this.plate && !!this.device && !this.running;
    this.startBtn.disabled = !(canLinear || canFull);
    this.startBtn.textContent = linear ? "Synthesize" : "Start";
    this.pauseBtn.disabled = linear || !this.running;
    this.stopBtn.disabled = linear || !this.running;
    this.continueBtn.disabled = linear || this.running || !this.sim || !this.sim.canContinue() || this.sim.samples >= Math.round(this.form.get().duration * this.form.get().fs);
    this.pauseBtn.hidden = linear; this.stopBtn.hidden = linear; this.continueBtn.hidden = linear;
    this.liveBtn.hidden = linear;
  }

  // ---------- Recording, view, playback ----------

  private installRecording(audio: Float32Array, frames: Float32Array[], p: SimParams, source: RunMode): void {
    this.rec = { audio, samples: audio.length, fs: p.fs, frames, fps: p.fps, source };
    this.spec.setOptions({ fs: p.fs });
    this.spec.setDuration(p.duration);
    this.spec.setSignal(audio);
    this.scrub.max = String(Math.max(0, frames.length - 1));
    if (frames.length > 0) {
      this.frameIndex = 0;
      if (this.view !== "mode") { this.setView("movie"); this.showFrame(); }
    }
    this.updatePeak();
    this.updateButtons();
  }

  private setView(v: ViewState): void {
    this.view = v;
    if (v === "design") { this.renderer.setField(null); this.overlay.textContent = this.plate ? "Stress-free shape" : ""; }
    else if (v === "live") { this.overlay.textContent = "Live"; if (this.sim) this.renderer.setField(this.sim.frames[this.sim.frames.length - 1]); }
    else if (v === "movie") this.showFrame();
  }

  private showFrame(): void {
    const rec = this.rec;
    if (!rec || rec.frames.length === 0) return;
    const f = Math.max(0, Math.min(rec.frames.length - 1, this.frameIndex));
    this.frameIndex = f;
    this.scrub.value = String(f);
    this.timeLabel.textContent = `${(f / rec.fps).toFixed(3)} s`;
    this.renderer.setField(rec.frames[f]);
    this.overlay.textContent = `${rec.source === "linear" ? "Linear" : "Full"} model, t = ${(f / rec.fps).toFixed(3)} s`;
  }

  private playable(): Float32Array | null {
    const rec = this.rec;
    if (!rec || rec.samples === 0) return null;
    const sig = rec.audio.subarray(0, rec.samples);
    return applyLevel(sig, levelGain(sig, rec.fs, this.levelMode, this.gainDb));
  }

  private updatePeak(): void {
    // Anything that changes the signal to be played (a new recording, the level mode, the gain) comes through here.
    this.hideLoudWarning();
    this.loudAccepted = false;
    const s = this.playable();
    if (!s) { this.peakLabel.textContent = ""; this.downloadBtn.disabled = true; this.playBtn.disabled = true; return; }
    const db = peakDbfs(s);
    this.peakLabel.textContent = `Peak ${db.toFixed(1)} dBFS${db > -0.5 ? " (clipping)" : ""}`;
    this.peakLabel.className = db > -0.5 ? "badge warn" : "badge";
    this.downloadBtn.disabled = false;
    this.playBtn.disabled = false;
  }

  private togglePlay(): void {
    if (this.player.playing) { this.player.stop(); this.playBtn.textContent = "Play"; this.spec.setCursor(null); return; }
    const s = this.playable(), rec = this.rec;
    if (!s || !rec) return;
    // A loud signal can hurt in headphones: warn before playing it, once per signal; any
    // change of the recording, the level mode or the gain asks again.
    const l = loudness(s, rec.fs);
    if (l.loud && !this.loudAccepted) {
      this.showLoudWarning(l.peakDb, l.shortTermDb, () => { this.loudAccepted = true; this.startPlayback(s, rec); });
      return;
    }
    this.hideLoudWarning();
    this.startPlayback(s, rec);
  }

  private startPlayback(s: Float32Array, rec: Recording): void {
    // Play from the scrubbed position only when the user has scrubbed to one; from the live
    // view, or from the end of the recording, start over.
    const atEnd = rec.frames.length > 1 && this.frameIndex >= rec.frames.length - 1;
    const start = this.view === "movie" && rec.frames.length > 1 && !atEnd ? this.frameIndex / rec.fps : 0;
    this.playBtn.textContent = "Stop";
    const prevView = this.view;
    this.player.play(s, rec.fs, start, () => { this.playBtn.textContent = "Play"; this.spec.setCursor(null); if (prevView === "live") this.setView("live"); });
    const tick = () => {
      if (!this.player.playing) return;
      const t = this.player.position();
      this.spec.setCursor(t);
      if (rec.frames.length > 1) { this.frameIndex = Math.round(t * rec.fps); this.view = "movie"; this.showFrame(); }
      requestAnimationFrame(tick);
    };
    requestAnimationFrame(tick);
  }

  private download(): void {
    const s = this.playable(), rec = this.rec;
    if (!s || !rec) return;
    const blob = encodeWav(s, rec.fs);
    const a = document.createElement("a");
    a.href = URL.createObjectURL(blob);
    a.download = `${(this.plate?.name ?? "cymbalsim").replace(/[^a-z0-9]+/gi, "-").toLowerCase()}-${rec.source}.wav`;
    a.click();
    setTimeout(() => URL.revokeObjectURL(a.href), 1000);
  }

  private updateTicks(): void {
    this.spec.setTicks(this.showTicks && this.modes ? Array.from(this.modes.freqs) : null);
  }

  // ---------- Tutorial ----------

  /** The state the tutorial's pages read. */
  private tutorialContext(): TutorialContext {
    const rec = this.rec;
    const st = this.sim ? this.sim.status() : null;
    return {
      plate: this.plate,
      design: this.design,
      params: this.form.get(),
      spacing: this.plateSpacing,
      sys: this.sys,
      modes: this.modes,
      model: this.model,
      lastContact: this.lastContact,
      recording: rec && rec.samples > 0 ? { source: rec.source, seconds: rec.samples / rec.fs } : null,
      full: st && st.totalSteps > 0 ? { peakForce: st.stick.maxForce, wmax: st.wmax, t: st.t, done: st.phase === "done" } : null,
      gpu: this.device !== null,
      runMode: this.runMode,
      spectrogram: { ...this.specOpts },
      memo: this.tutorialMemo,
    };
  }

  /** The actions the tutorial's pages can take. */
  private tutorialHost(): TutorialHost {
    return {
      ctx: () => this.tutorialContext(),
      loadPreset: async (id) => { this.editor.selectPreset(id); },
      loadScript: async (src) => { this.editor.setSource(src); this.onSource(src); },
      setParam: (key, value) => {
        if (key === "duration") {
          this.durationInput.value = String(value);
          this.durationInput.dispatchEvent(new Event("change"));
          return;
        }
        this.form.set(key, value);
        this.onParam(key, false);
      },
      computeModes: () => this.ensureModes(),
      showMode: (m) => this.modeBrowser.select(m),
      synthesize: async () => {
        if (this.runMode !== "linear") this.setRunMode("linear");
        await this.runLinear();
      },
      play: () => { if (!this.player.playing) this.togglePlay(); },
      setRunMode: (mode) => this.setRunMode(mode),
      runFull: () => this.runFull(),
      setSpectrogram: (o) => {
        if (o.window !== undefined) { this.specOpts.window = o.window; this.specWinSel.value = String(o.window); this.spec.setOptions({ window: o.window, hop: o.window / 8 }); }
        if (o.logFreq !== undefined) { this.specOpts.logFreq = o.logFreq; this.specLogChk.checked = o.logFreq; this.spec.setOptions({ logFreq: o.logFreq }); }
        this.tutorial?.refresh();
      },
      setViewOptions: (o) => {
        if (o.color !== undefined) { this.viewOpts.color = o.color; this.colorSel.value = o.color; }
        if (o.exaggeration !== undefined) this.viewOpts.exaggeration = o.exaggeration;
        this.renderer.setOptions(this.viewOpts);
      },
    };
  }

  // ---------- Tests ----------

  async selfTest(): Promise<string> {
    if (!this.device) return "no WebGPU";
    const lines: string[] = [];
    for (const id of ["flat-rectangle", "bowed-rectangle", "crash-16", "crash-bell-16", "ellipse"]) {
      const pr = presetById(id)!;
      const d = compileDesign(pr.source);
      const pl = evaluatePlate(d, 0.012);
      const r = await runSelfTest(this.device, pl, this.form.get());
      lines.push(`${id}: max relative error ${r.maxRel.toExponential(2)} (${r.n} nodes)`);
    }
    return lines.join("\n");
  }

  private testStatus(): unknown {
    return {
      design: this.design?.name ?? null,
      modes: this.modes ? { count: this.modes.count, missing: this.modes.missing, first: Array.from(this.modes.freqs.slice(0, 5)) } : null,
      synthesized: this.synthesized,
      running: this.running,
      samples: this.rec?.samples ?? 0,
      frames: this.rec?.frames.length ?? 0,
      source: this.rec?.source ?? null,
      peakPressure: this.rec ? Array.from(this.rec.audio.subarray(0, this.rec.samples)).reduce((m, v) => Math.max(m, Math.abs(v)), 0) : 0,
      sim: this.sim ? this.sim.status() : null,
      contact: this.lastContact ? { peakForce: this.lastContact.peakForce, contactTime: this.lastContact.contactTime } : null,
      editorStatus: ($("design").querySelector(".editor-status") as HTMLElement | null)?.textContent ?? "",
    };
  }
}

const app = new App();
app.init().catch((e) => {
  console.error(e);
  $("viewOverlay").textContent = `Failed to start: ${e instanceof Error ? e.message : String(e)}`;
});

export { app, PRESETS, isFlat, formatNumber };